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Updated: Jul 17, 2026

Determination of the Photoisomerization Quantum Yield of a Hydrazone Photoswitch
Published on: February 7, 2022
Single photon-induced symmetry breaking of H2 dissociation
F Martín1, J Fernández, T Havermeier
1Departamento de Química, C-9, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
Abstract:
H2, the smallest and most abundant molecule in the universe, has a perfectly symmetric ground state. What does it take to break this symmetry? We found that the inversion symmetry can be broken by absorption of a linearly polarized photon, which itself has inversion symmetry. In particular, the emission of a photoelectron with subsequent dissociation of the remaining H+2 fragment shows no symmetry with respect to the ionic H+ and neutral H atomic fragments. This lack of symmetry results from the entanglement between symmetric and antisymmetric H+2 states that is caused by autoionization. The mechanisms behind this symmetry breaking are general for all molecules.
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